"I believe in limited government, and the 20th century has been the century of government. The data is uniform. The government has failed at every single task it has set out to do, with the exception of waging war."
- Bart Kosko

A device which allows a group of people to empathize with a single person (like television lets many people view the same broadcast).

A new religion, replacing Zen Buddhism has swept out of the Middle West to engulf California. Wilbur Mercer appears on television, but says nothing.

Ray's voice was heavy with irony... "No one watches Mercer; that's the whole point." Tossing his cigarette into the fireplace, he strode to the TV set; there, before it, Joan saw a metal box with two handles, attached by a lead of twin-cable wire to the TV set. Ray seized the two handles, and at once a grimace of pain shot across his face.

"What is it?" she asked, in anxiety.

"N-nothing." Ray continued to grip the handles. On the screen, Wilbur Mercer walked slowly over the barren, jagged surface of a desolate hillside, his face lifted, an expression of serenity - or vacuity - on his thin, middle-aged features... To Joan, he explained, "This is the empathy box, my dear... when you take hold of these handles you're no longer watching Wilbur Mercer. You're actually participating in his apotheosis. Why, you're feeling what he feels."

The empathy box let you have the same experience - that of Wilbur Mercer. Everyone using an empathy box a particular time has the same experience; they share the feelings of Wilbur Mercer.

The empathy box is also used in Do Androids Dream of Electric Sheep?. In the world of the novel, most people have left the earth due to a radioactive dust that contaminates the planet, killing most animal life. The empathy box is a way for the few people who are left to reconnect with the majority of humanity who have left.

Here's a quote from the later novel:

"An empathy box," he said, stammering in his excitement, "is the most personal possession you have. It's an extension of your body; it's the way you touch other humans, it's the way you stop being alone.

Here's what PKD had to say about the concept, in relation to his novel:

Here, a religion is regarded as a menace to all political systems; therefore it, too, is a kind of political system, perhaps even an ultimate one. The concept of caritas (or agape) shows up in my writing as the key to the authentic human. The android, which is the unauthentic human, the mere reflex machine, is unable to experience empathy. In this story it is never clear whether Mercer is an invader from some other world. But he must be; in a sense all religious leaders are...but not from another planet as such.

Be sure to take a look at the Visi-sonor, from the Foundation series by Isaac Asimov, another invention with effects on different parts of the brain.